The present invention relates to an arrangement for measuring a force and/or a torque on a machine element extending along an axis with at least four magnetic field sensors using the inverse magnetostrictive effect.
From US 2012/0296577 A1, a magneto-elastic force sensor is known that is formed for the measurement of forces on an element that is magnetized circumferentially.
U.S. Pat. No. 5,321,985 teaches a magnetostrictive torque sensor in which a magnetostrictive layer is formed on the outer surface of a shaft and is positioned opposite excitation and detection coils. A torque acting on the shaft causes a material tension in the magnetostrictive layer, whereby its relative magnetic permeability changes as a function of direction. The magnetic field emerging from the magnetostrictive layer can be measured with the detection coils.
DE 699 36 138 T2 shows a magnetic force sensor in which a magnetized material is exposed to a bending moment, wherein the external magnetic field of the magnetized material can be determined with the help of a sensor arrangement.
From DE 603 09 678 T2, a method for detecting a torque in a shaft is known, in which magnetic fields are generated with alternating polarity that are measured with a sensor arrangement.
US 2007/0022809 A1 shows a device for the measurement of torques in which a layer is formed from a magnetostrictive material in a shaft.
From U.S. Pat. No. 5,052,232, a magneto-elastic torque sensor is known in which a machine element is provided with two circumferential magnetostrictive coatings.
From DE 698 38 904 T2, a torque sensor with a circular magnetization is known. The magnetization is formed in a ferromagnetic, magnetostrictive material of a shaft and extends in a circular shape about the shaft.
From DE 692 22 588 T2, a ring-shaped magnetized torque sensor is known.
WO 2007/048143 A2 teaches a sensor with a magnetized shaft.
WO 01/27638 A1 shows an acceleration sensor with a shaft that is magnetized circumferentially or longitudinally.
From WO 2006/053244 A2, a torque sensor is known that comprises a magnetization on a rotating shaft. The magnetization is formed circumferentially.
U.S. Pat. No. 8,191,431 B2 shows a sensor arrangement with a magnetized shaft.
EP 2 365 927 B1 shows a bottom bracket with two foot pedals and with a chain ring carrier that is connected to a shaft of the bottom bracket. The chain ring carrier is locked in rotation with a chain ring shaft that is connected, in turn, locked in rotation with the shaft. The chain ring shaft has a magnetization in some sections. A sensor is provided that detects a change in the magnetization in the event of a torque in the area of the magnetization.
U.S. Pat. No. 6,490,934 B2 teaches a magneto-elastic torque sensor for the measurement of a torque that acts on an element with a ferromagnetic, magnetostrictive, and magneto-elastic active area. This area is formed in a measurement transducer that sits, for example, on a shaft as a cylindrical sleeve. The torque sensor is opposite the measurement transducer.
From EP 0 803 053 B1, a torque sensor is known that comprises a magneto-elastic measurement transducer. The measurement transducer sits on a shaft as a cylindrical sleeve.
U.S. Pat. No. 8,893,562 B2 teaches a method for detecting a magnetic interference field for a torque measurement on a magneto-elastic shaft. Two signals are measured, wherein the second signal corresponds to the magnetic interference field and is subtracted from the first signal.
U.S. Pat. No. 8,001,849 B2 shows an arrangement for the magneto-elastic torque measurement in which the effect of external magnetic fields is to be compensated. The arrangement comprises a magnetized area of a shaft and also at least one passive and one active magnetic field sensor. The passive magnetic field sensors can be arranged on both sides of the magnetized area.
US 2011/0162464 A1 shows an arrangement for the magneto-elastic torque measurement in which the effect of equally shaped and unequally shaped magnetic fields is to be compensated. The arrangement comprises a magnetized area of a shaft and also at least three magnetic field sensors. The second and the third magnetic field sensor can be arranged next to the magnetized area.
U.S. Pat. No. 8,087,304 B2 shows a magneto-elastic torque sensor for the measurement of a torque acting on a shaft. The shaft has one or more circumferential magnetizations. FIG. 12 of U.S. Pat. No. 8,087,304 B2 shows an embodiment with only one circumferential magnetization, wherein two primary magnetic field sensors are arranged in the area of the magnetization and two secondary magnetic field sensors are arranged next to the area of the magnetization. FIG. 18 of U.S. Pat. No. 8,087,304 B2 shows an embodiment with two circumferential magnetizations that are polarized alternately, wherein also multiple magnetic field sensors are arranged at an axial transition between the two magnetizations. FIG. 8 of U.S. Pat. No. 8,087,304 B2 shows an embodiment with three circumferential magnetizations that are polarized alternately, wherein each magnetic field sensor is arranged in one of the areas of the three magnetizations. Through the special arrangement of the magnetic field sensors, the influence of magnetic interference fields is to be canceled.